1. The Theory of the Riemann Zeta-Function;Titchmarsh,1951
2. On the zeros of Riemann's zeta-function;Selberg;Skr. Norske Vid. Akad. Oslo,1942
3. The zeros of Riemann's zeta-function on the critical line;Hardy;Math. Z.,1921
4. Über Riemann's Nachlass zur analytischen Zahlentheorie;Siegel;Quellen und Studien zur Geschichte der Math. Astr. und Physik, Abt. B: Studien,1932
5. At least one third of the zeros of Riemann's zeta-function are on σ = 12;Levinson,1974